From 7b28c58d14ea0c6c4eddf67db53b0cb0c4cd1d2a Mon Sep 17 00:00:00 2001
From: Anton Akhmerov <anton.akhmerov@gmail.com>
Date: Mon, 23 Apr 2018 19:54:09 +0200
Subject: [PATCH] fix another bug in position calculation
---
zesje/helpers/pdf_helper.py | 15 +++++----------
1 file changed, 5 insertions(+), 10 deletions(-)
diff --git a/zesje/helpers/pdf_helper.py b/zesje/helpers/pdf_helper.py
index 0ce351034..774509f53 100644
--- a/zesje/helpers/pdf_helper.py
+++ b/zesje/helpers/pdf_helper.py
@@ -217,9 +217,6 @@ def process_page(output_dir, image_data, exam_config):
def extract_qr(image_data):
"""Extract a QR code from a PIL Image."""
grayscale = np.asarray(image_data.convert(mode='L'))
- # Apply portrait orientation.
- if grayscale.shape[0] < grayscale.shape[1]:
- grayscale = grayscale.T
# Empirically we observed that the most important parameter
# for zbar to successfully read a qr code is the resolution
@@ -229,7 +226,8 @@ def extract_qr(image_data):
for dirx, diry, factor in itertools.product([1, -1], [1, -1], [8, 5, 4, 3]):
scaled = grayscale[::factor * dirx, ::factor * diry]
scanner = zbar.Scanner()
- results = scanner.scan(scaled)
+ # Filter only QR codes to eliminate some false positives.
+ results = [i for i in scanner.scan(scaled) if i.type == 'QR-Code']
if len(results) > 1:
raise RuntimeError("Found > 1 QR code on the page.")
if results:
@@ -240,8 +238,6 @@ def extract_qr(image_data):
return
coords = np.array(results[0].position)
# zbar doesn't respect array ordering!
- if not np.isfortran(scaled):
- coords = coords[:, ::-1]
coords *= [factor * dirx, factor * diry]
coords %= grayscale.shape
return ExtractedQR(version, name, int(page), int(copy), coords)
@@ -258,19 +254,18 @@ def guess_dpi(image_array):
def rotate_and_shift(image_data, extracted_qr, qr_coords):
"""Roll the image such that QR occupies coords specified by the template."""
page, position = extracted_qr.page, extracted_qr.coords
+ y, x = np.mean(position, axis=0)
image = np.array(image_data)
if image.shape[0] < image.shape[1]:
- image = np.copy(np.transpose(
- image, ((1, 0) if len(image.shape) == 2 else (1, 0, 2))
- ))
+ image = np.transpose(image, [1, 0] + [2] * (len(image.shape) > 2))
+ x, y = y, x
dpi = guess_dpi(image)
h, w, *_ = image.shape
qr_widget = qr_coords[qr_coords.page == page]
box = dpi * qr_widget[['top', 'bottom', 'left', 'right']].values[0]
y0, x0 = h - np.mean(box[:2]), np.mean(box[2:])
- y, x = np.mean(position, axis=0)
if (x > w / 2) != (x0 > w / 2):
image = image[:, ::-1]
x = w - x
--
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